swift-导航栏添加自定义返回按钮

//1.添加返回按钮

func addBackBtn(){

let leftBtn:UIBarButtonItem=UIBarButtonItem(title: "返回", style: UIBarButtonItemStyle.Plain, target: self, action: "actionBack")

leftBtn.title="返回";

leftBtn.tintColor=UIColor.whiteColor();

self.navigationItem.leftBarButtonItem=leftBtn;

}

//返回按钮事件

func actionBack(){

self.navigationController?.popToRootViewControllerAnimated(true);

}